• 한국해양공학회지
• /
• 제35권6호
• /
• pp.414-425
• /
• 2021

Overcrowding of high-rise buildings in urban zones change the airflow pattern in the surrounding areas. This causes building wind, which adversely affects the wind environment. Building wind can generate more serious social damage under extreme weather conditions such as typhoons. In this study, to analyze the wind speed and wind speed ratio quantitatively, we installed five anemometers in Haeundae, where high-rise buildings are dense, and conducted on-site monitoring in the event of typhoon OMAIS to determine the characteristics of wind over skyscraper towers surround the other buildings. At point M-2, where the strongest wind speed was measured, the maximum average wind speed in 1 min was observed to be 28.99 m/s, which was 1.7 times stronger than that at the ocean observatory, of 17.0 m/s, at the same time. Furthermore, when the wind speed at the ocean observatory was 8.2 m/s, a strong wind speed of 24 m/s was blowing at point M-2, and the wind speed ratio compared to that at the ocean observatory was 2.92. It is judged that winds 2-3 times stronger than those at the surrounding areas can be induced under certain conditions due to the building wind effect. To verify the degree of wind speed, we introduced the Beaufort wind scale. The Beaufort numbers of wind speed data for the ocean observatory were mostly distributed from 2 to 6, and the maximum value was 8; however, for the observation point, values from 9 to 11 were observed. Through this study, it was possible to determine the characteristics of the wind environment in the area around high-rise buildings due to the building wind effect.

• 환경영향평가
• /
• 제16권6호
• /
• pp.503-510
• /
• 2007

Since 1990s many skyscrapers have been built in Seoul. However, gusty winds occur among tall buildings by descending turbulences due to the upper air blocking. This study aims to investigate the wind characteristics of skyscraper prevailing wind direction. In order to evaluate the building wind in this area, The wind speed and the wind direction were measured using propeller type RM-Young wind monitor in this study. The maximum wind speed was recorded by 15.1 m/sec and the main wind direction is WNW and NW. The ultimate purpose of this study is to figure out the phenomena of building wind impact and also to provide essential basic data for establishing proper guidelines in building wind impact assessment for skyscrapers in Korea.

• 해양환경안전학회:학술대회논문집
• /
• 해양환경안전학회 2003년도 추계학술발표회
• /
• pp.163-166
• /
• 2003

The seasonal mean wind direction and wind speed in a greater coasting area are investigated using the ECMWF(European Centre for Medium-Range Weather Forecasts) data for 11 years from 1985 to 1995. In winter, the main wind direction in Korea and vicinity, Taiwan and vicinity, and the North Pacific Ocean of middle latitudes is a northwesterly wind, northeasterly wind, and westerly wind respectively. The wind speed is strongest in the East China Sea, the South China Sea, and the North Pacific Ocean of low latitudes(Beaufort wind scale 5-6). A distribution pattern of wind direction in spring and fall is similar to that in winter. Seasonal mean wind speed is strongest in winter and the next is fall. The wind speed in summer is generally weak. However, that in the Indochina and vicinity is strong by the influence of Asian monsoon.

• Journal of Advanced Research in Ocean Engineering
• /
• 제4권2호
• /
• pp.53-65
• /
• 2018

The load condition significantly influences ship maneuverability in calm water. In this research, the effect of the load condition on turning performance of a very large crude oil carrier (VLCC) sailing in adverse weather conditions is investigated by an MMG-based maneuvering simulation method. The relative drift direction of the ship in turning to the wave direction is $20^{\circ}-30^{\circ}$ in ballast load condition (NB) and full load condition (DF) with a rudder angle $35^{\circ}$ and almost constant for any wind (wave) directions. The drifting displacement in turning under NB becomes larger than that under DF at the same environmental condition. Advance $A_d$ and tactical diameter $D_t$ become significantly small with an increasing Beaufort scale in head wind and waves when approaching, although $A_d$ and $D_t$ are almost constant in following wind and waves. In beam wind and waves, the tendency depends on the plus and minus of the rudder angle.

• 한국기계가공학회지
• /
• 제12권1호
• /
• pp.15-21
• /
• 2013

The safety and stability of 5MW class offshore wind turbine Jack-up platform was investigated through ocean basin experiment. For simulating the environmental condition of yellow sea in the South Korea, diverse waves, winds and currents were performed based on Froude's number. Regular wave and irregular wave based on Froude's number were applied to the wind turbine structure. In experiments, the height and period of regular wave type were scaled down as the 1:50 ratio of real wave condition. Irregular wave type was simulated with TMA(Texel Storm, Marsen and Arsloe)spectrum. The vertical reaction force, resonance period and wave pressure applied to multi-supporters of wind offshore structure were measured experimentally. Finally, the results showed that the capsizing situation of the offshore structure was generated by the severe environmental condition.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2013년도 춘계학술대회
• /
• pp.115-117
• /
• 2013

본 연구는 OSV(Offshore Support Vessel)의 운동응답 특성을 파악하기 위해 조우주파수와 선속변화에 따라 상하동요 및 종요에 대해 수치해석을 수행하였고 유효마력에 대한 실험값과 비교 해석하였다. 연구결과 뷰포드 스케일(Beaufort Scale) 2의 해상조건에서 조우각 $30^{\circ}$로 고속항주시 상하동요는 가장 크게 나타났고, 뷰포드 스케일 3 및 4일 경우 조우각 $90^{\circ}$로 저속항주시 상하동요가 가장 크게 나타났다. 종요의 경우, 뷰포드 스케일이 증가함에 따라 선형적으로 증가하였고, 조우각 $30^{\circ}$에서 고속항주시 가장 큰 값이 나타났다.

• 대한조선학회논문집
• /
• 제57권6호
• /
• pp.345-352
• /
• 2020

This study aims to investigate the crabbing motion of the research vessel "NARA" by full-scale maneuvering trials. The crabbing test method refers to ITTC recommended procedures and guidelines. In order to minimize the fluctuation of the heading angle due to the external force acting on the hull during the pure lateral motion, the tests are conducted using the dynamic positioning system applied to the ship. The test results are analyzed by applying a low-pass filter to remove the noise included in the measurement data. Three conditions are set to define the steady state of crabbing motion. The index to be derived from the crabbing test is quantitatively presented. The ship is confirmed to be capable of the lateral motion of up to 0.844m/s in Beaufort 3.

• 해양환경안전학회지
• /
• 제19권4호
• /
• pp.397-402
• /
• 2013

본 연구에서는 전장이 26.75 m인 해양플랜트지원선의 선형개발을 위한 수치해석을 수행하였고 수치해석 검증을 위한 1/10의 모형선 시험을 예인수조에서 수행하였다. 또한 운항해역의 해상조건으로 뷰포트 스케일 2, 3 및 4에서 향파, 선수사파 및 횡파에서 선속별 상하동요 및 종동요에 대해서 운동응답특성을 수치 해석하였다. 모형시험과 수치해석의 저항 예측 결과는 상호 일치하였다. 운동응답특성은 선수파에서 상하동요는 조우주파수 1.8~2.0 영역에서 크게 나타났으며, 종동요는 거친 해상에서 선미사파 및 고속영역에서 높은 운동특성을 보였다.

• 대한기계학회논문집B
• /
• 제28권6호
• /
• pp.734-739
• /
• 2004

The aerodynamic effect on platform during the train passage, the results of field test on the high-speed railway platform are discussed and the whole test results and conclusions are synthesized. The field test for the high-speed railway have been conducted on the Osong temporary platform in the newly constructed Seoul-Busan high-speed line and total 12 measurements have been conducted for G7 train and KTX train. The results shows that the high-speed trains have similar aerodynamic characteristics and have far better characteristics referring to the conventional trains such as Saemaul and Mugungwha trains. To discuss the actual aerodynamic effects on the platform at its own operational speed, Beaufort wind scale have been introduced and the criteria for the safety on railway platform has also been discussed.

• 대기
• /
• 제18권1호
• /
• pp.15-23
• /
• 2008

KMA (Korea Meteorological Society) and RSMC (Regional Specialized Meteorological Center) Tokyo - Typhoon Center isue 15/30 m/s radii in the TC (tropical cyclone) advisory for the information on the TC size. Meanwhile, JTWC Beaufort wind force scale, 34 kt and 64 kt correspond to the 'gale' and 'hurricane'. A ned to identify the range of the gale/hurricane wind from the TC bulletin of RSMC Tokyo or KMA that contains only 15/30 m/s radi motivates this study. An algorithm for estimating the radius of gale/huricane wind is developed by utilizing Holland's empirical formula on TC's wind-pressure relationship.